1 files changed, 85 insertions, 0 deletions
diff --git a/client-web/source/download_stream.ts b/client-web/source/download_stream.ts
new file mode 100644
index 0000000..5aafde1
--- /dev/null
+++ b/client-web/source/download_stream.ts
@@ -0,0 +1,85 @@
+/*
+    This file is part of keks-meet (https://codeberg.org/metamuffin/keks-meet)
+    which is licensed under the GNU Affero General Public License (version 3); see /COPYING.
+    Copyright (C) 2022 metamuffin <metamuffin@disroot.org>
+*/
+/// <reference lib="dom" />
+import { log } from "./logger.ts"
+import { send_sw_message, SW_ENABLED } from "./sw/client.ts"
+
+function FallbackStreamDownload(size: number, filename?: string, progress?: (position: number) => void) {
+    log({ scope: "*", warn: true }, "downloading to memory because serviceworker is not available")
+    let position = 0
+    let buffer = new Uint8Array(size)
+    return {
+        close() {
+            const a = document.createElement("a")
+            a.href = URL.createObjectURL(new Blob([buffer], { type: "text/plain" }))
+            a.download = filename ?? "file"
+            a.click()
+        },
+        abort() { buffer = new Uint8Array(); /* have fun gc */ },
+        write(chunk: Blob) {
+            const reader = new FileReader();
+            reader.onload = function (event) {
+                const arr = new Uint8Array(event.target!.result as ArrayBuffer);
+                for (let i = 0; i < arr.length; i++, position++) {
+                    buffer[position] = arr[i]
+                }
+                if (progress) progress(position)
+            };
+            reader.readAsArrayBuffer(chunk);
+        }
+    }
+}
+
+export function StreamDownload({ size, filename, cancel, progress }: {
+    size: number,
+    filename: string,
+    cancel: () => void,
+    progress: (position: number) => void
+}) {
+    if (!SW_ENABLED) FallbackStreamDownload(size, filename, progress)
+    let position = 0
+
+    // the sw will handle this download
+    const path = `/download/${encodeURIComponent(filename ?? "file")}`
+
+    const { port1, port2 } = new MessageChannel()
+    send_sw_message({ download: { path, size } }, [port2])
+
+    const a = document.createElement("a")
+    a.href = path
+    a.download = filename ?? "file"
+    a.target = "_blank"
+    // TODO this delay is part of a race condition btw
+    setTimeout(() => {
+        a.click()
+    }, 100)
+
+    port1.onmessage = ev => {
+        if (ev.data.abort) {
+            cancel()
+            port1.close()
+        }
+    }
+
+    return {
+        close() {
+            port1.postMessage("end")
+        },
+        abort() {
+            port1.postMessage("abort")
+        },
+        write(chunk: Blob) {
+            const reader = new FileReader();
+            reader.onload = function (event) {
+                const arr = new Uint8Array(event.target!.result as ArrayBuffer);
+                port1.postMessage(arr)
+                position += arr.length
+                if (progress) progress(position)
+            };
+            reader.readAsArrayBuffer(chunk);
+        }
+    }
+}